UC San Diego

Wind is a competitive, clean, and fast-growing renewable energy industry. However, in order for wind to compete with fossil fuel-based energies, it is necessary to achieve lower cost of energy. One way is to reduce operations and maintenance costs by integrating structural health monitoring (SHM) systems with wind turbines. It has been found that the fiber-reinforced polymer (FRP) composite-based wind blades are susceptible to damage (e.g., cracks, debonding, and impact). Damage is typically invisible to the naked eye and can propagate rapidly to cause sudden failure. This work presents a new SHM approach using embedded thin film sensors for detecting damage in FRP-based wind blades. While previous studies have shown that carbon nanotube-based thin films can be incorporated with FRPs for sensing, this study further investigates their electromechanical properties. First, a unique spray fabrication approach was employed so that films can be assembled on a low cost basis and can be deposited onto any substrate or structure. Second, the electrical properties of films subjected to post-fabrication thermal annealing were compared. Finally, freestanding films were prepared and subjected to uniaxial tensile cyclic loading while their resistivity was measured simultaneously. The results showed that these films were piezoresistive. © (2013) Trans Tech Publications.